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The Expression and Role of CD200 and CD200R1 in Peripheral Blood of Systemic Lupus Erythematosus

Author: WangYanXia
Tutor: TianXinPing；Zhang；LiYongZhe；ZhaoLiDan
School: Beijing Union Medical College
Course: Internal Medicine
Keywords: Systemic lupus erythematosus CD200 CD200R
CLC: R593.241
Type: Master's thesis
Year: 2011
Downloads: 42
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Abstract

ObjectiveCD200 and its receptor CD200R are both type-1 membrane glycoprotein of the immunoglobulin superfamily (IgSF) of cell surface proteins. CD200 is widely expressed on a variety of lymphoid and non-lymphoid cells, including thymocytes, T cells, B cells, follicular dendritic cells, neurons, endothelial cells, kidney glomeruli, the syncytiotrophoblast and smooth muscle cells. CD200R1--which is the main receptor of CD200--is primarily expressed by myeloid cells (e.g. macrophages, dendritic cells, neutrophils, monocytes, mast cells, et al). The binding of CD200 with its receptor CD200R1 plays an important role in down-regulating excessive inflammatory responses, preventing graft rejection, spontaneous abortion and the incidence of autoimmune diseases.Until recently, studies on the CD200-CD200R signaling pathway in autoimmune disease have been confined to autoimmune animal models, such as CIA, EAE, EAU, etc. as well as influences on the function of mast cells and macrophages. The knowledge of the biological function of CD200/CD200R axis in human body, especially in SLE patients was very limited and lack of report. In previous studies of our lab, we found that CD200 mRNA and CD200R1 mRNA was decreased in SLE patients. In this research, we detected the protein expression of CD200 and CD200R1 in the lymphocyte subsets and measured the serum levels of soluble CD200 in the peripheral blood from systemic lupus erythematosus(SLE) patients. And preliminarily studied the influence of recombinant human CD200/Fc fusion protein, CD200R1/Fc fusion protein and human CD200R1 affinity purification of polyclonal antibodies on the balance of T helper subsets and on the proliferation of CD4+T lymphocytes from SLE patients, so as to provide basis for further exploration of the role of CD200/CD200R signaling pathway in the pathogenesis of SLE.MethodsSeventy-four patients diagnosed of SLE were recruited. Forty-three sex and age matched health volunteers were accepted as healthy controls. Anti-coagulated peripheral blood was collected and mononuclear cells were isolated. Expression of CD200 and CD200R1 on peripheral T lymphocytes, B lymphocytes, dendritic cells, monocytes and NK cells were detected by flow cytometer. Serum levels of secreted CD200 were detected by ELISA.PBMC from SLE patients and health controls were cocultured with CD200Fc、CD200R1 Fc and anti-CD200Rl separately for 48 hours. Intracellular staining was processed and flow cytometry detection was analyzed to determine the percentage of Thl, Th2, Treg and Th17 cells.Certain amount of PBMC were also stained with CFSE under sterile conditions and cocultured with CD200 Fc, CD200R1 Fc or anti-CD200R1 in the presence or absence of stimulator (PHA or anti-CD3/CD28) for 96 hours. The status of proliferation was detected by flow cytometer.ResultsA. Expression of CD200 on subsets of lymphocytes from peripheral blood (%).1. SLE patients had higher percentage of CD200 expression on CD3+T lymphocytes than healthy controls (8.694±3.220 vs.6.340±2.439, P<0.01). What’s more, it seemed that higher percentage of CD200 expression on CD3+CD4+T lymphocytes from SLE patients than those from healthy controls (10.607±3.529 vs.7.549±2.957, P<0.01). But no significant differences of CD200 expression on CD3+CD8+ T lymphocytes were found between SLE patients and healthy controls (2.788±1.526 vs.2.706±1.118, P=0.838).2. No significant differences of CD200 expression on CD19+B lymphocytes were found between SLE patients and healthy controls (54.323±14.837 vs.59.887±9.593, P=0.198).3. No significant differences of CD200 expression on CD11c+CD123-mDC were found between SLE patients and healthy controls (4.977±1.737 vs.4.743±2.355, P=0.761). Nor did CD200 expression on CD11c-CD123+ pDC of SLE patients differ from healthy controls (14.084±4.337 vs.12.394±5.240, P=0.351).4. No significant differences of CD200 expression on CD 14+ monocytes were found between SLE patients and healthy controls (6.984±5.434 vs.14.185±13.395, P=0.054).5. No significant differences of CD200 expression on CD16+CD56+ NK cells were found between SLE patients and healthy controls (1.025±0.831 vs.0.662±0.253, P=0.135). B. Expression of CD200R1 on subsets of lymphocytes from peripheral blood (%).1. SLE patients had lower percentage of CD200R1 expression on CD3+ T lymphocytes than healthy controls (7.481±3.606 vs.12.703±4.869, P<0.01). Further detection found both CD3+CD4+ T lymphocytes (10.906±4.931 vs.18.448±5.423, P<0.01) and CD3+CD8+T lymphocytes (5.073±2.673 vs.7.489±4.502, P<0.05) from SLE patients down-regulated their expression of CD200R1.2. No significant differences of CD200R1 expression on CD19+B lymphocytes were found between SLE patients and healthy controls (11.300±12.643 vs.6.341±9.768, P=0.281).3. SLE patients had lower percentage of CD200R1 expression not only on their CD11c+CD123-mDC (45.239±12.808 vs.56.822±13.693, P<0.01), but also on their CD11c-CD123+pDC compared with healthy controls (46.196±19.459 vs. 72.125±10.173, P< 0.001).4. SLE patients had significantly lower percentage of CD200R1 expression on CD14+ monocytes than healthy controls (37.665±11.815 vs.68.661±8.437, P<0.001).5. No significant differences of CD200R1 expression on CD16+CD56+NK cells were found between SLE patients and healthy controls (27.781±18.319 vs.37.456±26.314, P=0.256).C. Serum levels of soluble CD200 were increased in SLE patients compared with healthy controls (306.60±72.63pg/ml vs.109.48±23.39pg/ml, p=0.001), but reduced to normal after immunosuppressive therapy (140.32±31.58pg/ml, p<0.001).D. The influence of CD200 signaling molecules on the balance of T helper cells in SLE and health controls was rather negligible.E. For SLE patients and healthy controls, both CD200 Fc and CD200R1 Fc have little influence on the spontaneous proliferation of PBMC. Nor did they have any effects on the proliferation of CD4+T cells under the stimulation of PHA or anti-CD3/CD28. But in SLE patients, CD4+T cells may respond to anti-CD3/CD28 stimulation more actively in the presence of anti-CD200Rl. ConclusionSLE patients had lower expression of CD200R1 on their CD4+T lymphocytes, CD8+ T lymphocytes, monocytes, pDC and mDC, but higher expression of CD200 on their CD4+ T cells. The serum levels of soluble CD200 were also increased in SLE patients, which returned to normal after immunosuppressive therapy.CD200 Fc, CD200R1 Fc and anti-CD200R1 all had little effect on the proportion of T helper cell subsets in SLE as well as in healthy controls. As shown by the proliferation experiments in vitro, anti-CD200Rl may promote the proliferation of CD4+T cells under the stimulation of anti-CD3/CD28. Data from above suggest that the CD200-CD200R pathway may play an important role in the pathogenesis of SLE.

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CLC: > Medicine, health > Internal Medicine > Systemic disease > Autoimmune diseases > Autoimmune diseases, connective tissue disease > Lupus erythematosus > Systemic lupus erythematosus
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